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Abstract: The micro-multi-functional actuator (MFA) of a cellular phone is a mass-spring system which is resonated by electrical force at the fundamental natural frequency to generate and transmit the vibration signal to the customers. The MFA has two design requirements such as high vibration force transmission and long fatigue life. Generally, conventional multi-functional actuators have been manufactured using stamped metal plate springs using precision dies. Since cracks are often generated in the cut area of metal plate during stamping operation, fatigue failures of conventional MFA’s are inevitable. In this study, a new micro-multi-functional actuator was designed using a spring (music) wire which has a high fatigue endurance limit because the surface of music wire is finely surface-finished. After the static and dynamic characteristics of MFA were analyzed using finite element analysis with respect to the diameter and shape of the spring wire, its dynamic performance such as fundamental natural frequency, vibration force transmission and fatigue life, and adhesion characteristics between the wire and the composite molding were experimentally investigated with respect to manufacturing parameters such as surface treatment method of spring wire, injection molding temperature and pressure of polymer mold. [Copyright &y& Elsevier]

Abstract: Substituting composite structures for conventional metallic structures has many advantages because composite materials have both high specific stiffness and damping characteristics compared to conventional metallic materials. In this study, circular plate cutting tools which are used for rough machining of bearing sites in crankshafts or camshafts were designed with the fiber reinforced composite material to reduce tool mass and to improve the dynamic stiffness of circular plate cutting tools. The hybrid steel/composite circular plate cutting tool was analyzed by finite element method with respect to material types such as composite and foam, stacking angles of the composite, adhesive bonding thickness, and dimensions of the cutting tool. Also, the constrained damping characteristics of the tools were experimentally investigated with respect to the adhesive bonding thickness and material type such as composite and PVC foam. From the finite element analysis and experimental results, optimal design parameters for the hybrid steel/composite circular plate cutting tool were suggested. [Copyright &y& Elsevier]